I hope no one will be shocked by yet another increase in the "official" autism rate in the US - if you are then you haven't been paying attention.
No, the only real question is how much higher the prevalence figure is going to be this time and what justifications the CDC will use to try to explain away the increase. Although, to be honest, neither of these things are really questions.
If history is any guide, I would expect the CDC's announcement to be based on data from eight year olds in 2008 and possibly 2010 as well. That would mean that we would be talking about children who were born in 2000 and 2002, respectively.
We have already seen some reports on children born during this time period in the 2007 National Survey of Children's Health, Massachusetts, Wisconsin, Utah, and Montreal (isn't Canada part of the US?). All of the data from all of these sources are pointing in one direction - up - and show a fairly consistent pattern.
So, based on those figures and the other historical CDC data, I would guess that the CDC's new figure will be somewhere in the range of 1 in 90 (120 per 10,000) to 1 in 80 (130 per 10,000) which would translate into roughly a 30% increase.
As for the reasons the CDC gives, well, I expect those to be almost identical to the one's from three years ago. They will say something along the lines of more awareness, more people willing and able to make a diagnosis, an increase in available services, better counting, and maybe, just maybe a small real increase in the rate.
Or in short, I fully expect 2012's announcement to be almost identical to the one in 2009. The CDC will announce a major increase in the autism rate, use the same tired lines to try and explain the increase, and tell us not to worry because they know is it an "urgent" health concern.
So get ready for Groundhog Day.